Method and apparatus for unloading bulk materials

ABSTRACT

An unloader for bulk materials is provided to transfer material such as cement from a barge or other bulk container. It includes a moveable and rotatable support member such as a crane or cantilevered arm that is adjacent the bulk container. A first conveyor or auger is connected to the support for pivotal movement and extends generally horizontally. A second conveyor or auger is connected to the distal end of the first conveyor for pivotal movement and is generally vertically oriented. A feeder unit is connected to the distal end of the second conveyor for universal and rotational movement. The feeder includes an uplift portion communicating with the second conveyor, the uplift portion advancing the bulk material at a rate slower than the second conveyor, and a collector portion communicating with the uplift portion. The collector portion includes converging auger assembly to advance the bulk material towards the uplift portion and to assist in transferring it into the uplift portion. The apparatus may further include a selectively operable energy responsive aeration system to inject air into the bulk material while it is being handled by the unloader, a scraper assembly attached to the feeder unit to assist in removing the last of the bulk material from its container, and a take-away assembly to transport the bulk material away from the unloader.

This is a continuation of copending application Ser. No. 08/007,542filed on Jan. 22, 1993, now abandoned which is a division of applicationSer. No. 07/750,971 filed Aug. 28, 1991, now U.S. Pat. No. 5,191,966,which is a division of application Ser. No. 07/549,895 filed Jul. 9,1990, now U.S. Pat. No. 5,078,261, which is a division of applicationSer. No. 07/144,428 filed Jan. 15, 1998, now U.S. Pat. No. 4,957,198,which is a division of application Ser. No. 848,907, filed Apr. 4, 1986,now U.S. Pat. No. 4,738,350, which is a continuation of application Ser.No. 672,151, filed Nov. 16, 1984, now abandoned, which is a continuationof application Ser. No. 414,383, filed Sep. 2, 1982, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates generally to the top unloading of bulk materialsfrom relatively large cargo containers or vessels, or the transfer ofbulk material from a cargo container to a material transport, handlingor storage system. More particularly, this invention relates to theunloading of dry powder-like cement or other loose, dry material from abarge or the like. It is especially useful where the container does nothave a self-contained unloading means or crane, or is not equipped witha gravity feed system. Moreover, the unloader of the present inventionmay be portable and self-contained, for operation from work barges,ships, or the like.

Dry cement is a fine powdered material (similar to talc) and is referredto hereinafter as "cement". Its size is very fine, 100 mesh or under; itis relatively free flowing at an angle of repose of 30° to 45°; and itis mildly abrasive. When aerated it becomes fluid-like, but whenpackaged or if it settles, it becomes very dense and difficult tohandle. Cement is widely utilized in construction because it has strongadhesive properties after it is combined with water. Once properlymixed, it sets in a few hours and cures or fully hardens over a periodof weeks.

Manufactured in large plants, the cement may be transported in bulkquantities by truck, rail or barge. However, due to its physicalproperties and fickle nature, cement requires a unique handling system.Small quantities may be conveniently unloaded or moved with a pneumaticsystem, but this has not proven efficient or effective for largerquantities. Thus, mechanical systems have been relied upon. However, dueto its powdery nature, the density of cement may vary from a relativelylight, fluffy and fluid-like or relatively free flowing aerated mixtureof less than fifty pounds per cubic foot, to a heavy, more solid andconcentrated mass of over 150 pounds per cubic foot.

Depending upon the conditions encountered upon loading and duringtransport, the cement may become tightly compacted, requiring amechanical, rather than pneumatic, unloader. In addition, when thecement is being transported, and even during the unloading process, themovement and vibration may cause the cement to settle or compact to itsmore dense state, causing pneumatic systems to plug and mechanicalsystems to jam, overload or bind. This usually results in undesirableand expensive down-time, accelerates wear and tear on equipment that isalready operating in a harsh environment, and may result in equipmentfailure. On the other hand, even when the cement is in its fluffyaerated condition, it poses unique handling and transport problemsbecause it is dust-like and requires a closed transport system tominimize pollution, loss, and wear of equipment due to abrasion. Thisalso protects the cement from exposure to elements which may contaminateit, or cause it to absorb moisture and harden. For this latter reason,it is important that the bulk container be emptied completely so thatresidual cement does not set up and harden each time the container isused.

Other bulk material unloading systems are available and known in theprior art, but most are gargantuan, requiring heavy capacity docksidecranes, ship derricks, or the use of gantry cranes that are supported bythe container or barge. Still others are not suitable for handlingcement. In addition, some of these unloaders required that the barge orcontainer be moved in order to reach all areas of the interior of thecontainer.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide an improved unloaderfor bulk materials, and particularly one that is capable of efficientlyhandling and unloading cement.

It is a further object of the present invention to provide an improvedunloader for transferring bulk materials from barges and other materialcontainers to a material transport, handling, or storage system.

It is a still further object of the present invention to provide animproved unloader that may reach all areas of the cargo container toremove nearly all of the bulk materials.

It is a still further object of the present invention to provide animproved unloader that will, if necessary, aerate the cement, andmaintain the density of the cement sufficiently low to minimize transferproblems.

SUMMARY OF THE INVENTION

The invention is embodied in an apparatus for unloading a supply of bulkmaterials. It includes a rotatable support means. A first conveyor meansis connected thereto and generally horizontally supported for pivotalmovement relative to the support. A second conveyor means is connectedto the first conveyor means and generally vertically supported forpivotal movement with respect to the first conveyor means. A feedermeans is attached to the second conveyor means proximate its distal endand includes an uplift portion and a collecting portion. The upliftportion is attached to the second conveyor means and advances the bulkmaterial at a rate slower than the second conveyor means.

The collecting portion is attached to the uplift portion and advancesthe bulk material from the supply to the uplift portion. In operation,the bulk material is moved by the collecting portion into the upliftportion, moved into the second conveyor means, transferred to the firstconveyor means, and discharged therefrom. The invention may furtherinclude an aeration system to inject air into the bulk material duringtransport by the unloading apparatus, a set of scrapers mounted on saidfeeder means to assist in removing the last portions of the bulkmaterial from the container, dust-tight conveyors to minimize loss andcontamination of the material, and a take-away system to carry the bulkmaterial to another location after it has been unloaded.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the unloading apparatus of the presentinvention illustrating the feeder head engaging the bulk material andwith the scraper means raised.

FIG. 2 is a perspective, partially exploded and cutaway view of thesecond or generally vertical conveyor means of the present invention,and its pivotal connections to the first or generally horizontalconveyor means.

FIG. 3 is a perspective, partial cutaway view of the feeder head of thepresent invention, with one of the scraper means in a lowered position.

FIG. 4 is a perspective view of a take-away means of the presentinvention as it is usually disposed, i.e. underneath the support means,to receive the unloaded bulk material. The base of the support means isillustrated in phantom lines.

FIG. 5 is a perspective view of an alternate embodiment of the unloadingapparatus of the present invention.

FIG. 6 is a perspective, partial cutaway view of an alternate embodimentof a portion of the present invention, illustrating the pivot connectionbetween the first and second conveyor means being suspended fromoverhead.

FIG. 7 is a perspective, partial cutaway view of an alternate embodimentof a portion of the present invention, illustrating a connection betweenthe first or generally horizontal conveyor means and a take-away means.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As seen in FIG. 1, a barge 2 or other vessel or container of bulkmaterial 3 is floated and secured next to a dock structure 4, pier, orother unloading area by cable 6 or the like to maintain it in position.The bulk material unloading apparatus 8 is adjacent the edge of the dockstructure 4 and selectively moves parallel to the barge on rails ortracks 10. The unloader 8 generally comprises a support means 12, afirst conveyor means 14, a second conveyor means 16, and a feeder means18. Each of these components is discussed in detail in the followingdescription, with reference to the drawings.

As illustrated, a set of tracks or rails 10 runs parallel to the bargeto support and selectively transport the unloading apparatus 8 withoutmoving the barge. Alternatively, the unloading apparatus could bemounted on crawler tracks (see FIG. 5) or mounted on rails for movementperpendicular to the length of the barge. In addition, it may bedesireable or more convenient to move the barge rather than theunloading apparatus.

The support means 12 includes an undercarriage 20 that comprises trucks22 of conventional design having suitably journaled wheels 24 retainedtherein. The wheels illustrated are double flanged, i.e. H-shaped whenviewed from a radially distant position, and are complimentary to therails 10. Suitable motive and braking means (not shown) may power orlock the wheels as necessary or desireable to effect movement or retainthe undercarriage in position along the length of the rails 10.

A support platform 26 is superposed the undercarriage 20 and ispreferably selectively rotatably mounted thereon, for crane-like,rotational or panning movement about a vertical axis independent of theundercarriage. The platform 26 forms a convenient base for any motivepower necessary for the unloader. A boom 28 has its proximal endattached to the platform 26 in a conventional manner for pivotalmovement in a vertical plane. The boom may be of any convenientconfiguration provided that its length is sufficient to reach from thesupport 12 to approximately the center of the barge 2, and furtherprovided that it will support the weight of the conveyor means, feedingmeans, and material in transit.

A pair of extensible cylinders 30A, 30B, suitably controlled byhydraulic fluid or the like, raise and lower the boom, and retain it ina selected vertical position as desired by the operator. The cylinders30A, 30B may be of any type well known in the art, as may be theircontrols, and they typically extend between a somewhat centrally locatedstandard 32 on the boom and a portion 34 of the platform displaced fromthe proximal end of the boom 28 where it is attached to the platform.The cylinders are preferably double action to exert additional downwardforce if necessary. In addition, they may incorporate a balance featurewhich exerts sufficient upward pressure on the boom to minimize theweight imposed on the feeder head, yet still keep it in contact with thecement.

An operator's cab 36 is positioned adjacent the boom to provide anunobstructed view of the bulk material container. All controls for theoperation of the unloader and equipment monitoring its operation may belocated in the cab.

The first conveyor means 14 is an auger that is generally horizontallysupported by, and may be attached to, the boom 28 in a convenientmanner. In FIG. 1, it is attached to the underside of the box-like boom28, and, as an alternative, it may be suspended from a boom asillustrated in FIG. 5. In FIG. 1, the first conveyor comprises a mainportion 40A and a yoke portion 40B, 40C, all three portions beingsupported by the boom 28. Each portion is an auger or screw typeconveyor. The augers for each portion are preferably single screws, eachhaving suitable bearings provided as necessary, such as 46, and each maybe powered with a bidirectional variable speed hydraulic motor. Thesegenerally horizontal augers may be of uniform pitch to provide a uniformfeed along their entire length. A relatively long or high pitch ispreferred to maintain rapid movement of the cement. Further details onauger design are discussed in connection with the second or generallyvertical auger.

Referring also now to FIG. 2, and using like numerals to designate likeitems, the entrance or intake portion 42B, 42C of each respective sideof the yoke portion 40B, 40C is disposed proximate the distal end of thefirst conveyor means, and is adjacent one end of an internal screw-likeauger 44. The discharge end 48B, 48C of the respective yoke portionstransfer the bulk material from the yoke augers to each side of theintake end 50 of the main portion 40A of the first conveyor means, whichdischarges preferably near the center of rotation of the support means12. The sheath or housing for each auger may be cylindrical orrectangular, and is preferably dust-tight.

The second conveyor means 16 is pivotally connected to the distal end oryoke end of the first conveyor means, and is generally verticallysuspended therefrom. Like the first conveyor means 14, the secondconveyor means is an auger or screw type conveyor, similarly powered,with an intake 52 at the distal end 53 and a pair of oppositelydirected, tubular, tangentially extending discharge portions 54A, 54B atthe proximal end 55.

Referring primarily to FIG. 2, the conveyor or auger sheath 56 houses anauger shaft 58 having a single helical flight 60, or alternativelymultiple flights, attached along the length thereof. The auger sheath iscylindrical, to match the auger screw, and it may be disposed within asecond housing sleeve, such as the box-like one designated 57, foradditional support. The flight increases in pitch from intake todischarge along at least a portion of the length of the second conveyorbeginning at the intake to help maintain a loose or aerated state of thematerial. A set of paddles 61 is radially attached to the auger shaft 58in spoke-like fashion directly adjacent the discharges 54A, 54B toassist in tangentially discharging the material from the second auger tothe intakes of the yoke portions 40B, 40C. A hydraulic motor 62 isattached to the auger sheath and coaxial with the auger shaft. The motoris connected to the auger shaft 58 through a thrust bearing 64.

Each discharge 54A, 54B comprises a tubular conduit 55A, 55B extendingfrom and at right angles to the length of the second conveyor 16, andeach is received by a flange plate 56A, 56B defining mating sleeveapertures 63. The flange plates each releasably secured to, with itsaperture 63 coaxial with, the intake 42C for the respective yoke portion40B, 40C of the first conveyor means. When assembled, as shown in theupper right portion of FIG. 2, each discharge or proximal end 54A, 54Bof the second conveyor means is pivotally mounted in dust-tight relationto the distal end of the first conveyor means, being disposed in thespace defined between the two yoke portions 40B and 40C. Assembly orrepair is facilitated by, typically, nut and bolt fastening means 65.

The first and second conveyors are maintained in a common plane and theangle between them may be selectively maintained or changed by anextendible cylinder 66 having one end attached to the first conveyor 14and a second end attached to the proximal end 55 of the second conveyor16 by suitable means, such as a cap 55A which is situated on or near thetop of the second conveyor means. Such a cylinder may be hydraulicallyactuated by a conventional control located in the cab 36.

The bearings along the length of the augers deserve special attentiondue to the abrasive nature of the cement, which may result in a shortoperational lifetime. As a result, conventional bearings are notsuitable. One of the more successful designs utilized by applicantscomprises a hard iron cylindrical race with a hardened steel auger shafttherethrough. There is a loose fit between the two and the cementimpregnates the two wearing surfaces of the bearing and fills the spacebetween them to act as a buffer zone to lubricate and cool the wearingsurfaces. However, if the auger is run at a relatively high rate ofrevolution, the cement is centrifugally cast to the periphery of theauger flighting and the bearing has no cement for lubrication. This canresult in rapid deterioration of the bearing and shaft. This problem hasbeen satisfactorily resolved by precision manufacturing of the augerscrew and casing sections, so both are straight or very nearly so, asopposed to having a bowed or banana shape along their length. And, byminimizing the clearance between the auger screw flighting and thesurrounding casing, the linear alignment of the auger shaft may be heldwithin smaller tolerances. This further provides an unexpectedimprovement in efficiency of operation by minimizing slippage of thecement between the auger screw and casing, and permitting operation inthe range of 300 to 500 revolutions per minute, which is generallyconsidered to be high speed operation.

Referring now to FIGS. 1-3, the distal or intake end 53 of the secondconveyor means 16 includes a split receiving collar 68 fixedly attachedto the auger sheet. The collar conforms to an annular flange 70 (seeFIG. 3) disposed around the top periphery or discharge end of the feedermeans 18. The collar 68 is clamped or compressed circumferentially by abolt and nut set 69 to engage over the flange 70 and rotatably retain itin dust-tight relation so that the uplift portion 72 of the feeder means18 is colinear with the second conveyor means 16. A hydraulic motor 71or the like is attached to the second conveyor means 16 by attachment tothe underside of a plate 75, with a sprocket and chain drive 71'operatively connecting it to the uplift portion 72. Operation of themotor will cause the entire feeder head 18 to rotate around its augeraxis in either direction with respect to the second conveyor means 16 byturning the flange 70 within the collar 68.

Referring more particularly to FIG. 3, the feeder means 18 includes anuplift portion 72 and a collecting portion 74. The collecting portionincludes a pair of counter-rotating augers 80, 82 that cause the bulkmaterial to converge near the center of the collecting portion, and theuplift portion is an auger conveyor that moves the converged materialupwardly to the entrance of the second or vertical conveyor means 16. Amore detailed description follows.

The collecting portion 74 has an open, rectangular frame 76 withdepending V-shaped brackets 78 on each end thereof. The brackets supporta pair of unenclosed augers 80, 82 for fixed parallel rotationalmovement. Each auger has a single central shaft 84, 86 connected to itsrespective bracket by a suitable enclosed, internal hydraulic drive 88,89 to rotate the auger shafts in opposite directions. Each auger shaftis divided into two sections of substantially equal length, such as 80Aand 80B, each having flighting of opposite pitch so that rotation of theshaft conveys material from each journalled end of each shaft to thecenter of the collecting portion. In addition, the diameter of eachauger half for each shaft decreases from the journalled end to thecenter portion, resulting in a tapered flight conveyor.

The central portion 90 of the frame 76 is connected to the inlet portion92 of the uplift section for universal movement by a gimbal arrangement,i.e. movement similar to that of a universal joint in an automobiledrive shaft or that of a gyrocompass. Specifically, rocking motion(i.e., pivoting about an axis perpendicular to the auger shafts 84, 86and perpendicular to the axis of the uplift section 72) is accomplishedby attaching to the frame 76, on opposing interior sides thereof,circular plates 94A, 94B that are mounted for free rotation along anaxis perpendicular to the auger shafts 84, 86 and perpendicular to thelongitudinal axis of the auger shaft for the uplift section 72. Thecircular plates 94A, 94B are connected together for simultaneousrotation by cross members 96 along opposite sides of uplift portion 72and each having a length slightly longer than the outside diameter ofthe sheath for the uplift section. (The cross member on the oppositeside is not shown.) Each cross member includes a centrally locateddepending tab 98, each tab having an aperture 100. This tab permitspitching motion of the frame 76 about an axis parallel to the augershafts 84, 86 and perpendicular to the axis of the uplift section 72.This is accomplished by connecting the exterior of the sheath for theuplift section 72 to the depending tab 98 by a pintle 102 extendingthrough apertures 100. The pintle extends parallel to the auger shafts84, 86 and perpendicular to the axis of the auger shaft for the upliftsection 72. In this fashion, the circular plates 94A, 94B and the crossmembers 96 comprise a sub-frame that is rotationally mounted to theframe 76 of the feeder 18.

The orientation of the collecting portion 74 with respect to the upliftsection 72 may be controlled by two sets of opposing extensiblecylinders 104-106 (one of the cylinder is not illustrated), such ashydraulic cylinders. The four cylinders are radially disposed around theaxis of the uplift conveyor, each 90° from its adjacent cylinders. Oneend of each cylinder is attached to the uplift section 72, and theopposite end of each cylinder is attached to the collecting portion,preferably its frame 76. Movement may be induced by other suitablemeans, and it may be limited by the use of mechanical stops.

Also attached to the frame 76, preferably on opposite sides parallel tothe axes of the auger shafts 84, 86, are a pair of independentlyoperable scraper plates 110, 112. Each plate is attached to the frame byseparated pairs of spaced, hinged arms, such as 114, 116 in FIG. 1,which form a parallelogram linkage and permit the plates to be raisedand lowered. The parallel arms permit the lower edges 110A, 112A todescend to a position at least as low as the lowest portion of theaugers 80, 82 so that each edge may come into contact with the floor ofthe barge or container. Controllable extensible cylinders 118, 120,raise and lower the scraper plates 112 and 110 respectively. One end ofeach cylinder is attached to the uplift section 72, and the opposite endis connected to the corresponding scraper plate.

The uplift portion 72 includes a screw auger 73 extending upwardly fromthe center portion of the frame 76 for the collecting portion 74. Theintake 121 of the uplift portion is a slightly tapered exposed screwauger (i.e., not covered by a housing sheath) which extends downwardbelow the illustrated frame 76 and cross members 96 and between thecenter sections of the two collecting augers 80, 82. The diameter of theuplift auger 73 is substantially the same as the auger for the secondconveyor means 16, e.g., 12 inches, except that it tapers from 12 inchesto approximately 10 inches where exposed on the lowermost or intake end121. The degree and amount of taper may be varied as desireable. Thetapered intake end is disposed approximately midway between thecounter-rotating rotating auger shafts 84, 86 of the collecting portion74, along a common radius connecting the axial center of each shaft.

The uplift auger 73 is a double flight short pitch screw conveyor, itspitch being less than that of the vertical or second conveyor means 16.This provides more efficient movement of cement by reducing slippage,and a more constant or even flow.

The discharge end 77 of the uplift section includes the annular collar70 for selective rotational attachment to the second conveyor means 16,as described earlier. The uppermost end 73A of the auger shaft 73 isconnected to the auger shaft 58 of the second conveyor means, whichprovides rotational driving force. Although the two augers rotate at thesame speed, the second conveyor means 16 advances the material at afaster rate due to its greater pitch. This dedensifies the cement tomaintain it as an aerated fluffy compound and prevent it from packing.The uplift auger is approximately four feet long and the vertical augeris approximately 24 feet long, although these lengths may vary asnecessary or desireable.

Referring now to FIG. 4, there is illustrated a take-away means 130 ofthe present invention. Referring also to FIG. 1 the take-away means isdisposed underneath the support means 12 in a channel 131 defined by thesupports 133 for the rails 10, and preferably is coextensive with thelength of the barge 2 to permit the operator of the unloader maximumrange of movement. The take-away means generally includes a funnel 132that collects material discharged from the proximal end of the first orgenerally horizontal conveyor means 14, and a conveyor means 134extending parallel to the tracks 10 to transport the material to anotherlocation.

The frusto-conical funnel top 132 is preferably suspended, by anyconvenient means, from the support platform 26 or trucks 20 of thesupport means 12, and moves therewith. The discharge of the firstconveyor is disposed above the center of the funnel 132, and both arepreferably centered at the vertical axis of rotation of the supportmeans. The connection between the discharge of the conveyor 14 and thefunnel 132 is preferably dust-tight. A pair of discharge chutes 136, 138are connected to and disposed beneath the funnel top 132 to confine andslideably transport the material away from the funnel. The chutes 136,138 are bifurcated or elbowed to form a transverse aperture 140therebetween.

The conveyor means 134, including a frame 135, may be a conventionalscrew-type or belted conveyor, whichever is appropriate for the materialbeing handled. As illustrated, the conveyor is covered by a fixedflexible belting 142 of suitable weight and width, such as knownconveyor belting, that forms a generally dust-tight seal with the top ofthe screw conveyor 134. Tapered guides 144 be positioned along thelength of the conveyor at its upper edges as necessary to assist inpositioning the cover.

A carriage 146, suspended from the moving funnel 132 or riding on top ofthe conveyor frame 135, lifts and guides the cover through thetransverse aperture 140 beneath the funnel top 132. The carriage may beof convenient design and use rollers, guides or skids 148 to continuallylift and hold the cover 142 off the conveyor frame at the situs of thedischarge chutes 136, 138, as the apparatus 8 traverses therealong ontracks 10, yet maintain the cover in a closed dust-tight relationship atall other locations.

Referring again to FIGS. 1 and 3, an aeration system is utilized toinject compressed air into the cement or other material to "fluff" it,or disperse it to prevent it from becoming too densely packed. A supplyof compressed air (not shown) may be conveniently located in the supportmeans 12 and is connected to a conduit 150 that is attached to andtraverses the length of the first and second conveyor means 14 and 16. Asuitable flexible tubing 152 may be utilized as necessary to accommodatepivot or universal connections. A series of nozzles 154 placed one everyseveral feet, conducts the compressed air through the sheath 56 of theauger conveyor means to inject air into the cement. This effectivelykeeps the cement in suspension. The nozzles may be installed in as manylocations as necessary or desireable, depending upon the conditionsencountered.

Air is injected by a mechanism, well known in the art, that isresponsive to the torque requirements to power the auger screw. As thecement begins to pack more densely, more torque is required, as measuredby the magnitude of the pressure drop across the hydraulic supply lineand return line to the hydraulic motor rotating the screw. When thepressure differential exceeds a predetermined level, the aeration systemis activated to inject air and thereby lessen the cement density andreduce the torque requirements. At the present time, applicant utilizesthree nozzles along the length of the vertical or second conveyor means.The pressure of the air supply tank is maintained at about 150 poundsper square inch, and, upon actuation, air is injected into the augerperpendicular to its length at a rate of about 50 cubic feet per minute.The air injection provides an almost immediate reduction in density andreduction of torque requirements, which terminates the air injectionafter about one second. Due to the ability of cement to harden after itbecomes wet, it is especially desireable to eliminate any condensatefrom the compressed air system.

Referring now to FIG. 5, an alternate embodiment of the presentinvention is illustrated, although many of the components and elementsof this alternate embodiment are identical to those described andillustrated in FIG. 1. A barge 202 is secured to a dock 204 by a cable206. The unloader 208 is adjacent the dock and may selectively move asnecessary or desired. The unloader comprises a support means 212, afirst conveyor means 214, a second conveyor means 216, and a feedermeans 217.

The support means 212 differs from that in FIG. 1 mobility to theunloader. However, this additional mobility may interfere with theinstallation of a permanent take-away system, as illustrated in FIG. 4.

The boom 219 is pivotally attached to the support means in aconventional manner, and its position and movement may be controlled inany known fashion. The first conveyor means 214 passes through the boom219 and is suspended therefrom by cables 218 and pulleys 220 to adesired height. The discharge end 222 of the first conveyor is proximatethe center of rotation of the support means 212 and superposed a funnelshaped discharge chute 224.

The discharge chute 224 may empty into a take-away conveyor (not shown)positioned in a convenient location. For example, it may extend from thetop 226 of the support means 212, or it may extend from between thetracks 213 below the support means, collecting the material after it hasbeen discharged by the first conveyor means and fallen the depth of thesupport means to a location beneath it.

The distal or intake end 228 of the first conveyor means 214 ispivotally connected to the discharge or proximal end 230 of the secondconveyor means. An extendible cylinder 232, one end connected to thefirst conveyor 214 and the other end connected to the second conveyor216, selectively controls the angle between the two. A dust-tightflexible boot or slide 239 may be utilized to transport the cementdischarged from the second conveyor 216 to the intake of the firstconveyor 214.

The feeder means 217 is as described earlier herein.

Referring to FIG. 6, an alternate embodiment is illustrated for theconnection and suspension of a first or generally horizontal conveyormeans 250 and a second or generally vertical conveyor means 252. The twoconveyor means are connected for pivotal movement in parallel adjacentsubstantially common planes. The first conveyor 250 has its dischargeend (not illustrated) supported by means such as illustrated in FIGS. 1and 4. The intake or distal end 254 is supported in a conventionalmanner by a pin 256 and clevis 258 arrangement that is suspended from anoverhead arm or the like (not illustrated) by cables 260. The secondconveyor 252 is vertically suspended from the pin and clevis and ispivotally connected thereto. The discharge of the second conveyor 252communicates to the intake of the first conveyor 250 through a collar orpassageway 262 located radially outwardly from the auger paddles 263which are attached to the auger shaft 264 for rotational movementimmediately adjacent the discharge collar 262. The angle between the twoconveyors may be selected and maintained by an extendible cylinder 266as disclosed earlier. The auger 268 for the second conveyor means 252may be driven by a hydraulic motor 270 through a bearing 272, asdisclosed earlier.

Referring now to FIG. 7, an alternate embodiment is illustrated for theorientation and movement of the support means and for the take-awaymeans. A barge 280 is secured next to a dock structure 282 to maintainit in position. A set of tracks or rails 284 extends perpendicular tothe length of the barge to support and selectively guide the unloadingapparatus. A set of trucks 286, such as disclosed in FIG. 1, rollinglyengages the rails 284 and transports the support means, which is notillustrated but is similar to that already disclosed. The proximal end288 of the first conveyor means 290, which is suitably supported,includes a discharge 292 proximate the center of rotation of the supportmeans. Immediately below and connected to the discharge, a flexiblejoint 294 permits the first conveyor to be raised, lowered, or pivoted,yet still maintain a dust-tight enclosure. The discharge end 296 of theflexible joint is connected to the intake of a telescoping gravity slide298. The discharge end 300 of the slide 298 is connected to the intakeend 302 of a take-away conveyor 304, also suitably supported. Theflexible joint 294 permits the telescoping slide 298 to change itsorientation with respect to the support means yet still maintain adust-tight seal.

DESCRIPTION OF THE OPERATION

Referring primarily to FIGS. 1-4, a barge is secured adjacent to anunloading area 4 and the unloading means 8 is moved into position by itstrucks 22 moving along the rails 10. The boom 28, already being in araised position, is lowered by shortening the extendible cylinders 30A,30B. Simultaneously, the second conveyor means 16, including the feedermeans 18, is extended with respect to the first conveyor means 14, andthe boom 28, by contracting the extendible means 66 to enlarge the anglebetween the two conveyor means. The boom is lowered by the cylinders30A, 30B until the converging augers 80, 82 of the feeder means comeinto contact with the cement 3 or other bulk material.

With all of the conveyors being energized, the augers 80 and 82 of thefeeder means are rotated in opposite directions by their respectivehydraulic motors to draw the cement to the center of the collectingportion 74. The exposed auger flighting moves the material to the centerand causes it to converge around the exposed, tapered, double flightauger of the uplift portion 72. Although the intake portion of theuplift auger does not have a sheath, the material packs around theintake to define a quasi-sheath and load the auger screw with materialfor upward transport.

The uplift portion 72 moves the cement upwardly towards the dischargeend of the uplift portion which is coincident with the intake portion ofthe second conveyor means. The uplift portion provides a relativelysteady and even rate of discharge of material.

The second conveyor means 16, having an auger with a higher pitch thanthe auger of the uplift portion, accelerates the cement upwardly,lessening its density and improving its flow-ability. The cementcontinues upwardly to the discharge of the second conveyor where it istransferred to the intake 42B, 42C of the yoke portion 40B, 40C of thefirst conveyor 14. The cement continues along the auger yoke portion tothe discharge end 48B thereof, which is in communication and coincidentwith the intake of the first conveyor 40A. The cement is transferredalong the first conveyor means 40A by the auger contained therein and isdischarged into the funnel 132 disposed immediately therebelow. Thecement passes through the funnel into the discharge chutes 136, 138,underneath the raised belting 142, and into the take-away conveyor 134.The cement is then transferred to another location or stored.

As the cement is moved by the augers, it may pack or become more dense,requiring more torque to rotate the augers. Should the torque exceed apredetermined level, the aeration system is energized to supplycompressed air along conduit 150 to the nozzles 154, which inject airinto the vertical conveyor, or other conveyors as necessary, and fluffor aerate the cement, making it less dense and lessening the torquerequirements to rotate the auger.

The operator may rotate the feeder means 18 with respect to the secondconveyor means 16 as necessary by selective operation of the hydraulicmotor 71, and he may tilt or pitch the feeder means with respect to theuplift section 72 by manipulating the opposing extendible cylinders104-106. In addition, the operator may change the radial position of thefeeder head by panning the support means about its axis of rotation, orchange its depth by raising or lowering the boom 28 and flexing orextending the first conveyor means with respect to the second conveyormeans through the operation of the extensible cylinder 66. This providesa back hoe-like operation and permits the operator to reach into thevarious corners of the barge and beneath any lips surrounding the top ofthe barge.

Due to the propensity of cement to absorb moisture and harden, it isdesireable to remove all of the cement from the barge. The presentinvention facilitates the ability to do that by lowering the scraperplates 110 or 112, as necessary, to scrape the bottom, walls or cornersof the barge. Absent the scraper plates, a layer of cement about 1/2 afoot deep will most likely be left in the bottom; with the scraperplates lowered, this may be reduced to one inch or less, depending uponthe flatness of the barge floor.

The invention has been described in detail with particular reference toa preferred embodiment and selected alternative and the operationthereof, but it is understood that other variations, modifications, andthe substitution of equivalent mechanisms can be effected within thespirit and scope of this invention, particularly in light of theforegoing teachings. For instance, one may substitute a belted conveyorfor the first or generally horizontal conveyor provided that the beltedconveyor is maintained in a generally horizontal position.

What is claimed is:
 1. A method of transferring a supply of aeratablebulk powder material disposed at a first location to a predeterminedsecond location, said method comprising successively advancing portionsof the bulk powder material to a predetermined area of the firstlocation; successively moving at a first rate the advanced bulk powdermaterial portions in a first closed conveyor portion from thepredetermined area in a generally vertically oriented direction to afirst elevated station; successively moving at a second rate faster thanthe first rate the bulk powder material portions from the first elevatedstation in a generally vertically oriented direction and in a secondclosed conveyor portion communicating with said first conveyor portionto a second elevated station above said first elevated station thereuponconveying the bulk powder material portions in a generally laterallyoriented direction from the second elevated station to the secondlocation.
 2. The method of claim 1 wherein each of said closed conveyorportions is an auger conveyor.
 3. The method of claim 2 includingselectively aerating the bulk powder material portions while the latteris moving between the first and second elevated stations.
 4. The methodof claim 3 including aerating the bulk powder material portions independence upon the power demands in moving the bulk powder materialportions from the first to the second elevated stations.
 5. The methodof claim 3 wherein jets of a compressed gaseous medium are directed intothe bulk powder material portions as the latter move from the firstelevated station to the second elevated station.